Those killed in the crash on the Indiana Toll Road include a 21-year-old mother and her two sons, one of whom was 6 weeks old. The other victims were a 52-year-old man and his 15-year-old son, and a 26-year-old woman and her 8-year-old daughter, said Indiana State Police Sgt. Trent Smith.
Three other people from the minivan were hospitalized.
A relative in the Chicago neighborhood of Albany Park said the whole family was from Ecuador and many lived in the Chicago area. Segundo Quishpi said he last saw his cousin Cayetano Quizhpe and his cousin's family on Tuesday for a big family gathering.
"They lived well, and they brought no trouble," he said.
State police said the victims were members of an extended family composed of three family groups.
One family was identified as Cayetano Quizhpe, 28, who was listed in stable condition. His wife, 21-year-old Maria J. Yupa, and sons, 8-year-old Edwin Quizhpe and 6-week-old Franklin Quizhpe, were killed. Quishpi said the couple had been together many years.
A second family included Pedro Chimborazo, 52, who was killed along with his 15-year-old son, Pedro Chimborazo Yupa. His wife, Maria Antonia Yupa, 36, was listed in serious condition.
The other two killed were Maria Chimborazo Pinguil, 26, and her 8-year-old daughter, Jessica Chimborazo. The driver of the minivan, 30-year-old Manuel Chimborazo, was listed in critical condition, state police said.
An acquaintance of the families in Albany Park, Maria Yupa, 34 (no relation to the victims), said the men in the families worked in construction. She said it's common in the part of Ecuador they're from for people to have the same name. She said the 8-year-old girl, Jessica Chimborazo, was close to her grandfather and liked to dance and use the computer.
None of the minivan's 10 occupants were wearing seatbelts during the crash Thursday night about 10 miles east of South Bend, Smith said. Smith said the infant was in a car seat but had not been buckled in.
The minivan was heading east on the toll road about 8 p.m. Thursday when it hit a deer and stopped or slowed down, authorities said. The semitrailer was going about 65 mph when it hit the van in the highway's eastbound lanes shortly after that.
Both vehicles ended up in the center median, blocking traffic in both directions for several hours. Firefighters and emergency workers at the scene of the crash swarmed around the crumpled remains of the minivan, its side shredded with a torn hunk of metal pinned beneath one of the semi-tractor's tires.
The driver of the semi-trailer - Jesse Donovan, 24, of Johnston, R.I. - was released from a hospital after being treated for minor injuries. Smith said he didn't face any charges at this time and preliminary tests indicated that he had not been drinking alcohol.
Donovan was an employee of Roehl Transport Inc. of Marshfield, Wis., which owns the truck, said Vice President of Workforce Development and Administration Greg Koepel.
"Our hearts go out to those in the accident and their families," said Koepel, who said the company would have no further comment.